1. Field of the Invention
This invention relates to additives which are useful as dispersants and/or detergents in lubricating oils. In particular, this invention is directed toward polyamino alkenyl or alkyl succinimides which have been modified by treatment with a thiocarbonate of the formula: ##STR2## wherein R.sub.4 is an alkylene group of from 2 to 3 carbon atoms or an alkylene group of from 2 to 3 carbon atoms substituted with from 1 to 3 alkyl groups of from 1 to 2 carbon atoms each. The modified polyamino alkenyl or alkyl succinimides of this invention have been found to possess dispersancy and/or detergency in lubricating oils. These modified succinimides are also useful as dispersants and/or detergents in fuels.
2. Prior Art
Alkenyl or alkyl succinimides have been previously modified with alkylene oxides to produce poly(oxyalkylene)hydroxy derivatives thereof. These alkylene oxide treated succinimides are taught as additives for lubricating oils (see U.S. Pat. Nos. 3,373,111 and 3,367,943). Karol et al, U.S. Pat. No. 4,482,464, disclose succinimides which have been modified by treatment with a hydroxyalkylene carboxylic acid selected from glycolic acid, lactic acid, 2-hydroxymethyl propionic acid and 2,2'-bis-hydroxymethylpropionic acid. These modified succinimides of Karol et al are disclosed as lubricating oil additives. Anderson, U.S. Pat. No. 3,301,784 discloses mono- and bis-(N-hydrocarbyl(alkylsubstituted)-2-pyrolidinones as dispersant additives for lubricating oils. Heiba, U.S. Pat. No. 4,182,715 discloses the reaction of gamma-alkyl-gamma butyrolactones having an alkyl substituent of at least 16 carbon atoms in length with amines or polyalkylenepolyamines. The products of this reaction are disclosed as multifunctional agents in lubricants, fuels, coolants and other organic fluids. Babic, U.S. Pat. No. 4,439,612 discloses the reaction of carbon disulfide with hydrocarbyl succinimides to form thioureas. The thioureas disclosed therein are useful in gasoline and diesel engine dispersancy, oxidation stability and friction modification. However, there is no teaching in these patents or apparently elsewhere of the modified alkenyl or alkyl succinimides of this invention.